I don't know what the problem is.......This thing has never ran right since I've had it.It runs fine from 85mph to close to 150 where I stopped,but running around town.........it sucks.
I had the intake off,and a single 4Bbl for the move cause someone else was going to be driving the car,and put the intake back on in the last couple evenings,and it is running worse than it ever has.It is backfiring out the drivers side(Passenger side 3 carbs feed this),and it has lost power under load.
I checked the plugs,checked the wires,re-adjusted the valve lash,made sure all the carbs were tight,and on,and on......
I have a fairly healthy solid lift cam w/about 544 lift,and not alot of vacuum,which is a no-no for this set up,but HAVE had it running better than this.Grrrrrrrrr........
I'm ready to pull it,and go back to a single 4........
HELP from someone smarter than I!!!!!!!!!!!!!!!

 

Which carbs do you have? Ever rebuild the carbs? I had to go through both my tripower setups. The last one twice. Removing and replacing them can stir up debris in the float bowls and clog internal passages and introduce crap into the lines. All it takes is a tiny piece of debris in one needle valve or a piece of dislodged varnish in a jet or internal orfice to screw up your whole deal. Had sticky needle valve (new)on the front and rear carbs and was able to get a check ball upgrade. The 2 bbls are very basic and real easy to rebuild. Once you do the first one the rest are a piece of cake. I know it seems like a lot of hassle but once you get them setup right it is a real cool induction system. Yours is twice as cool! The rochesters I have won't run right with over 5 pounds of fuel pressure stock. The new check ***** will take 7 to 9 pounds without an issue. You might have too much fuel pressure for those old carbs. A lot of the old 2 bbls need 3.5 to 5 pounds of fuel pressure or you overpower the float and needle valve. The floats are small. The symptoms are they run rich and bog down a lot at low RPM but run pretty good when you get the RPM up. I put an inline regulator and fuel pressure guage in it. Now, with the new check valve needle and seat replacement I can fine tune my A/F ratio on the nitrous with the regulator with no effect on the carb and without disassembling the nitrous system to change jets.
I would buy six rebuild kits, disassemble, clean and rebuild the carbs and make sure the float levels are adjusted correctly, install an inline regulator, fuel pressure guage and set it @ 4 pounds and install a new inline filter before the regulator and guage. If it seems to lean out at sustained high RPM you can always crank the pressure up but it probably won't ever need more. You have 6 float bowls, plenty of fuel reserve and the old GTO tripowers ran on 4PSI. If your carbs are rochesters PM me and I will hook you up with the upgraded check ball needle and seat replacements. Another issue could be your 2 front and two rear carbs which are secondaries could be leaking air around the throttle plates. This will cause idle issues and low rpm problems. WOT will be fine. I found an aftermarket baseplate for mine made out of aluminum with brass, lapped in throttle plates that sealed perfect. When you disassemble them take the baseplate and look at it up to the light. You should see no gap anywhere where light shines through on the front and rear plates. I have a fix for this too if you have a problem.

 

Kevin.....thanks for the reply.
What I really am thinking,and have is,it is the butterflies not sealing properly,and when I crack it open it goes into a lean condition until I can get it going.
I am running a electric fuel pump w/2 regulators,and the old school copper line that comes into the console for the pressure reading.I have the regulator cranked down to run between 3-4 psi,and the needle/seat screws....1,and 3/4s on the centers,and 3/4s on the 4 corners.
It could be debris too.I had them off,and in my shop back in Illinois,and could have gotten something down in there.
I KNOW that I am tired of messing w/this!
I ordered the wrong Eddy air gap for a guy,and have it coming to me here,and may run it w/my 750dp until I get the 6x2 rebuilt.
These are custom Holley 2110s w/ no power valve provisions,and were rebuilt about a year ago.
Like I said....they never have been right unless I was running top-end,but were ALOT better befpre all this.....
Thanks for the response Kevin.
My wife says.......just take them off,.and get rid of them,and I say......shoiw me another vette anywhere w/this induction,and I will sell them.
Cheers Kevin!
Kevin

 

Are you running them with a progressive linkage where you run and idle on the centers and as you accelerate the end carbs kick in. You need no idle circuits and well sealed throttle plates on the end carbs, There is a 12 degree throttle base plate available with no idkle circuits that seal well for the end carbs. If your running a linkage where all carbs have idle circuits and linkages all work uniformly you won't get it to idle or accelerate well at the bottom end. Too big of initial pump shot then too much air when you crack them open. The center carbs need to be primaries with idle circuits, choke and power valve, the end carbs secondaries with no idle circuit or choke provisions, no power valve They are dumpers only, linkage progressive. Also the stock accelerator pumps have a leather cup. These are crap. There is a new style rubber cup available. Check Vintagespeed.com for parts. I know it was a lot of work to get my first tripower working correctly. Once I did it worked better than the 4 bbl it replaced and was troublefree. It wasn't cheap or easy though. Call me if you want. 8156955022